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71.
Vendula Pachlová František Buňka Leona Buňková Sabina Purkrtová Šárka Havlíková Irena Němečková 《International Journal of Dairy Technology》2016,69(3):386-392
The aim of this work was to study the biogenic amine content of brine‐ripened cheeses after one year of storage and then to investigate possible contaminating micro‐organisms with decarboxylase activity. The biogenic amine production of isolates was tested in vitro. The most frequent biogenic amines were putrescine, histamine and tyramine. The biogenic amine content detected in one cheese sample was above 120 mg/kg; this can be considered toxicologically relevant. Decarboxylase activity was found for 33 contaminating micro‐organisms. Isolates belonging to Bacillus licheniformis, Debaryomyces hansenii, Staphylococcus equorum and Serratia marcescens produced significant amounts of putrescine and cadaverine. 相似文献
72.
Matousková P Luxová A Matousková J Jiros P Svatos A Valterová I Pichová I 《Chembiochem : a European journal of chemical biology》2008,9(15):2534-2541
The knowledge of the molecular basis of communication in bumblebee communities is limited. None of the enzymes that participate in pheromone production have been characterized. Here, we cloned the gene encoding the Delta(9) desaturase from cDNA prepared from the total RNA of the pheromone gland and fat bodies of Bombus lucorum male. Functional expression of BlucNPVE desaturase in Saccharomyces cerevisiae and GC-MS analyses revealed its preference for C(18) saturated fatty acids. This suggests that Delta(9) desaturase is involved in the desaturation of metabolic fatty acids stored in triacylglyceroles (TAGs), because oleic acid is the most abundant fatty acid bound in TAG in B. lucorum and it is present in low concentration in the pheromone blend. The incubation of pheromone precursors with a dissected labial gland as well as direct injection of labelled pheromone substrates into B. lucorum males revealed that esterification of pheromone products occurs in the labial gland. These results support both the biosynthesis of pheromones from common lipids and the de novo synthesis of unsaturated pheromones in the labial gland. 相似文献
73.
74.
Katarzyna Kozlowska Marta Jeruszka Irena Matuszewska Wojciech Roszkowski Nina Barylko-Pikielna Anna Brzozowska 《Food quality and preference》2003,14(8):653-661
The objective of this study was to evaluate the predictive value of hedonic tests on apple juice carried out in a sensory laboratory, University common room and at home (post-consumption test) on ad libitum home consumption measured over 5 consecutive days. Thirty-five elderly volunteers (59–88 years old) and 33 young subjects (20–30 years old) assessed the degree of liking five apple juices varying in sweetness (0, 2, 4, 7 and 10% w/w sucrose added) on a nine-point hedonic scale. Both age groups judged similarly the juice with the lowest sugar concentrations, whereas the juice with 2% sugar added received lower scores from the elderly compared to the young participants. Those samples with higher sweetness (4, 7 and 10%) received higher scores from the elderly compared to the young people. The sample with no sugar added had higher mean score (all the subjects) in the home test (6.92±1.78) compared to both laboratory (5.51±2.15) and common room (5.92±2.08). No such differences were observed for the juices with the other sugar contents. In the elderly group, 1-day intake of apple juice remained on a similar level, regardless of sweetness liking, while among young adults the intake varied, and was highest for juices that were liked most (with 0 and 2% sucrose added). The results showed that hedonic ratings have a limited value as predictors of fruit juice consumption at home. The correlation between rated degree of liking and intake was low, especially for the elderly (r=0.39), indicating that factors other than pleasantness may affect intake. Among three test conditions, the lowest correlation of juice intake was obtained with laboratory test results (r=0.38), relatively higher—when hedonic tests were conducted in common room setting (r=0.49), or as the post-consumption test at home (r=0.73). Further research is required on sensory procedures relevant for the elderly, which together with some other nonsensory factors, would give a better prediction of consumption. 相似文献
75.
Vladimir Kocourek Ludmila Havlíková Irena Zemanová 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,185(1):14-16
Summary The kinetics of the photodegradation of synthetic pyrethroids (permethrin, cypermethrin and deltamethrin) on the surface of treated grain were investigated. Pyrethroids are quickly degraded if spread in a thin layer on a glass plate and photodecomposition proceeds more slowly on UV-irradiated grain. Moreover, in the latter case the degradation of pyrethroids was incomplete. The residual levels of all compounds after 15 min UV-irradiation depended on the storage time which elapsed between treatment of the grain and irradiation. The results indicate that the synthetic pyrethroids are able to penetrate inside the grain and that the UV-irradiation technique could be a tool to study this penetration.
Die Photostabilität der synthetischen Pyrethroide auf Getreide
Zusammenfassung Die Kinetik der Zersetzung durch Licht synthetischer Pyrethroide (Permethrin, Cypermethrin und Deltamethrin) auf der Oberfläche von Getreidekörnern wurde untersucht. Pyrethroide, die in einer dünnen Schicht auf eine Glasplatte gesprüht sind, zerfallen schnell, ihre Zersetzung auf der Oberfläche des Getreidekornes erfolgt nach UV-Behandlung langsamer. Die Zersetzung der Pyrethroide war unter diesen Bedingungen unvollständig und der Gehalt an Rückstand hängt bei allen Pyrethroiden (nach 15 min UV-Belichtung) von der Zeit zwischen Körnerbehandlung und Belichtung ab. Diese Ergebnisse weisen darauf hin, daß die synthetischen Pyrethroide ins Korninnere dringen können und daß die Technik der UV-Behandlung für die Untersuchung dieser Effekte verwendet werden kann.相似文献
76.
Irena B. Agater Kenneth J. Briant Jeffery W. Llewellyn Ronald Sawyer Francis J. Bailey Christopher H. S. Hitchcock 《Journal of the science of food and agriculture》1986,37(3):317-331
The detection and measurement of characteristic peptides formed on enzymatic hydrolysis of soya protein products, meats and offals is described. Samples were heated at 120°C for 3h prior to digestion with trypsin overnight, and the resultant peptide mixtures passed through an Amicon ultrafiltration membrane. After concentration the ultrafiltrates were analysed by ion exchange chromatography on Aminex A5 resin. Peptides were detected by post-column reaction with ninhydrin. Characteristic peaks designated SP 2 and MP 1 were seen in chromatograms of digests of soya protein isolate and beef respectively, and these peaks were well resolved in beef and soya protein isolate mixtures. The SP 2 peak was shown to contain peptides derived from soya 11 S globulin. The soya protein and beef contents of a series of mixtures of freeze-dried, defatted beef and soya protein isolate were determined by measurement of the SP 2 and MP 1 peaks respectively. Soya protein content could be determined within 2% of the true value over the range 30–70% soya protein isolate and beef content could be determined within 5% of the true value in the range 20–100% beef. Analysis of five soya protein isolates, four soya protein concentrates, six soya flours and 13 textured soya products indicated considerable interproduct variation in the yield of SP 2. The MP 1 peak was seen in a range of meats, both cooked and raw. It was also present in digests of offals which contained smooth or striated muscle but not in ‘non-muscle’ offals. The protein origin of the MP 1 peak was not established but the yield appeared lower in meat products which had been heated during manufacture than in those which had received no such treatment. Analysis of a series of laboratory prepared canned and heated pork and soya protein isolate mixtures enabled the pork content to be determined to within 8% of the true value, 2% soya protein isolate could be detected but not quantified accurately. 相似文献
77.
Hájek M Dezortová M Wagnerová D Skoch A Voska L Hejlová I Trunečka P 《Magma (New York, N.Y.)》2011,24(5):297-304
Object
Among several non-invasive methods of liver fat analysis, the most important role is played by MR imaging and spectroscopy (MRS). This study describes the 1H MRS at 3T measurement of liver fat volume fraction ffat{\phi_{{\rm fat}}} in a group of liver transplant patients, an at-risk group for the development of de novo steatosis. 相似文献78.
Jan Suchanicz Irena Jankowska-Sumara Tatiana V. Kruzina 《Journal of Electroceramics》2011,27(2):45-50
Lead-free Na0.5Bi0.5TiO3 -BaTiO3 ceramics have been prepared in the whole range of concentrations and studied at room-temperature by means of X-ray, Raman
scattering and infrared techniques. X-ray measurements revealed rhombohedral, rhombohedral-tetragonal boundaries and tetragonal
modifacations depending on the contents of BaTiO3. The distinct changes of the Raman and infrared spectra with increasing of BaTiO3 content, which were correlated with X-ray results, were observed. The broad phonon spectra indicated the disorder in the
A site of Na0.5Bi0.5TiO3 -BaTiO3 system. 相似文献
79.
Sagnella SM Gong X Moghaddam MJ Conn CE Kimpton K Waddington LJ Krodkiewska I Drummond CJ 《Nanoscale》2011,3(3):919-924
We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipid prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation. 相似文献
80.
Elena Pâslaru Lidija Fras Zemljic Matej Bračič Alenka Vesel Irena Petrinić Cornelia Vasile 《应用聚合物科学杂志》2013,130(4):2444-2457
A two‐step procedure was applied to obtain antimicrobial films; this procedure involved a corona treatment of the polyethylene (PE) surface and its chemical activation with 1‐ethyl‐3‐[3‐dimethylaminopropyl] carbodiimide hydrochloride and N‐hydroxysuccinimide, and this led to the covalent bonding of chitosan on the PE surface. Electrochemical methods were used to investigate the stability of the deposited chitosan layer. The potentiometric and polyelectrolyte titrations showed that some amount of chitosan desorbed faster from the surface until equilibrium was reached and also that the grafted chitosan layer was more stable than the physically adsorbed one. The chitosan immobilized on the PE surface exhibited the expected antibacterial activity when tested against three bacteria, which included two Gram‐negative bacteria, Salmonella enteritidis and Escherichia coli, and one Gram‐positive bacterium, Listeria monocytogenes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2444–2457, 2013 相似文献